
April 24, 2014 17:29 PSP Book - 9in x 6in 03-Rashid-A.-Ganeev-c03
60 Low-Order Harmonic Generation in Plasma Plumes
ablation and fundamental beams were present. The second order
of some atomic Cu emissions appears in the 430–440 nm region.
Experiments performed with ablation and fundamental laser pulses
of picosecond duration emitting at 1064 nm yielded efficient TH
for the three metal plasmas, but no signal was detected for the FH,
due to the low efficiency of the spectral acquisition system at the
corresponding wavelength.
Figure 3.2 shows the behavior of the TH as a function of the pulse
energy of the nanosecond ablation laser for each of the three metals. ...